Download or read book Gamma Ray Pulsar Studies With GLAST written by and published by . This book was released on 2011 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Some pulsars have their maximum observable energy output in the gamma-ray band, offering the possibility of using these high-energy photons as probes of the particle acceleration and interaction processes in pulsar magnetospheres. After an extended hiatus between satellite missions, the recently-launched AGILE mission and the upcoming Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) will allow gamma-ray tests of the theoretical models developed based on past discoveries. With its greatly improved sensitivity, better angular resolution, and larger energy reach than older instruments, GLAST LAT should detect dozens to hundreds of new gamma-ray pulsars and measure luminosities, light curves, and phase-resolved spectra with unprecedented resolution. It will also have the potential to find radio-quiet pulsars like Geminga, using blind search techniques. Cooperation with radio and X-ray pulsar astronomers is an important aspect of the LAT team's planning for pulsar studies.
Download or read book Finding Or Not New Gamma Ray Pulsars with GLAST written by and published by . This book was released on 2011 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Young energetic pulsars will likely be the largest class of Galactic sources observed by GLAST, with many hundreds detected. Many will be unknown as radio pulsars, making pulsation detection dependent on radio and/or x-ray observations or on blind periodicity searches of the gamma-rays. Estimates for the number of pulsars GLAST will detect in blind searches have ranged from tens to many hundreds. I argue that the number will be near the low end of this range, partly due to observations being made in a scanning as opposed to a pointing mode. This paper briefly reviews how blind pulsar searches will be conducted using GLAST, what limits these searches, and how the computations and statistics scale with various parameters.
Download or read book GLAST LAT And Pulsars written by and published by . This book was released on 2007 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma-ray pulsars are among the best targets for the Large Area Telescope (LAT) aboard the GLAST mission. The higher sensitivity, time and energy resolution of the LAT will provide data of fundamental importance to understand the physics of these fascinating objects. Powerful tools for studying the LAT capabilities for pulsar science are the simulation programs developed within the GLAST Collaboration. Thanks to these simulations it is possible to produce a detailed distribution of gamma-ray photons in energy and phase that can be folded through the LAT Instrument Response Functions (IRFs). Here we present some of the main interesting results from the simulations developed to study the discovery potential of the LAT. In particular we will focus on the capability of the LAT to discover new radio-loud gamma-ray pulsars, on the discrimination between Polar Cap and Outer Gap models, and on the LAT pulsar sensitivity.
Download or read book Pulsar Astronomy with GLAST written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite their name, the rotation powered neutron stars called 'radio pulsars' are actually most luminous in the hard x-ray and gamma-ray bands. GLAST will be the first high-energy satellite with sufficient sensitivity to detect and study large numbers of these pulsars. I will review GLAST's key science goals in pulsar astrophysics and summarize the extraordinary advances in low-energy pulsar surveys since the days of CGRO.
Download or read book Gamma Ray Pulsars written by David J. Thompson and published by BiblioGov. This book was released on 2013-06 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-energy gamma rays are a valuable tool for studying particle acceleration and radiation in the magnetospheres of energetic pulsars. The seven or more pulsars seen by instruments on the Compton Gamma Ray Observatory (CGRO) show that: the light curves usually have double-peak structures (suggesting a broad cone of emission); gamma rays are frequently the dominant component of the radiated power; and all the spectra show evidence of a high-energy turnover. For all the known gamma-ray pulsars, multiwavelength observations and theoretical models based on such observations offer the prospect of gaining a broad understanding of these rotating neutron stars. The Gamma-ray Large Area Space Telescope (GLAST), now in planning for a launch in 2006, will provide a major advance in sensitivity, energy range, and sky coverage.
Download or read book The Multi Messenger Approach to High Energy Gamma Ray Sources written by Josep M. Paredes and published by Springer Science & Business Media. This book was released on 2007-11-12 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a theoretical and observational overview of the state of the art of gamma-ray astrophysics, and their impact and connection with the physics of cosmic rays and neutrinos. With the aim of shedding new and fresh light on the problem of the nature of the gamma-ray sources, particularly those yet unidentified, this book summarizes contributions to a workshop that continues today.
Download or read book Revealing the Most Energetic Light from Pulsars and Their Nebulae written by David Carreto Fidalgo and published by Springer. This book was released on 2019-07-17 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on the extraordinary observation of TeV gamma rays from the Crab Pulsar, the most energetic light ever detected from this type of object. It presents detailed information on the painstaking analysis of the unprecedentedly large dataset from the MAGIC telescopes, and comprehensively discusses the implications of pulsed TeV gamma rays for state-of-the-art pulsar emission models. Using these results, the book subsequently explores new testing methodologies for Lorentz Invariance Violation, in terms of a wavelength-dependent speed of light. The book also covers an updated search for Very-High-Energy (VHE), >100 GeV, emissions from millisecond pulsars using the Large Area Telescope on board the Fermi satellite, as well as a study on the promising Pulsar Wind Nebula candidate PSR J0631. The observation of VHE gamma rays is essential to studying the non-thermal sources of radiation in our Universe. Rotating neutron stars, also known as pulsars, are an extreme source class known to emit VHE gamma rays. However, to date only two pulsars have been detected with emissions above 100 GeV, and our understanding of their emission mechanism is still lacking.
Download or read book Gamma Ray Emissions from Pulsar Binaries written by Chun-Kwan Leung and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Gamma-ray Emissions From Pulsar Binaries" by Chun-kwan, Leung, 梁晉堃, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: The launch of the Fermi Gamma-ray Space Telescope marked a new era in observing gamma-rays from astrophysical sources. Fermi's high sensitivity in the 0.1-300GeV energy range opens an important window in the observation of the gamma-ray emissions from pulsar binaries, which emit most of their radiation energy in the gamma-ray range. We can now observe the gamma-ray emissions from pulsar binaries at an unprecedented accuracy, and investigate their origin in detail. In this thesis, we present the studies on two systems of pulsar binary of two distinct classes. The gamma-ray emissions from the high-mass gamma-ray binary LS 5039 were studied using the latest data from Fermi. The emission is modulated according to the 3.9 hr orbital period of the system. The results can be explained by the contribution of three components: the pulsar magnetospheric emission, the pulsar wind emission and the emissions from the shock formed from the interaction between the pulsar wind and companion's stellar wind. The results were compared with observed data from Fermi and also in X-ray and TeV. In addition, the emissions from the millisecond pulsar PSR J1023+0038 and its low mass binary companion were also studied. This system recently went through a transition from the rotation-powered state to the accretion state, after going the opposite way in 2007. This state transition, discovered through the disappearance of radio pulsation, was accompanied by the brightening in GeV, X-ray and UV fluxes. A detailed Fermi observation was performed, supplemented by multi-wavelength observations. It was found that the emission from this system can also be described by the emissions from the pulsar magnetosphere, the pulsar wind and its shock. These two systems, although of distinct classes of pulsar binaries, provide complementary cases for the study of high-energy radiation processes in pulsar binaries. DOI: 10.5353/th_b5317064 Subjects: Gamma ray astronomy Pulsars
Download or read book Radio Loud and Radio Quiet Gamma Ray Pulsars from the Galactic Plane and the Gould Belt written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present recent results of a pulsar population synthesis study in the polar cap model that includes the Parkes Multibeam Pulsar Survey, realistic beam geometries for radio and [gamma]-ray emission from neutron stars born in the Galactic disc as well as the local Gould Belt. We include nine radio surveys to normalize the simulated results from the Galactic disc to the number of radio pulsars observed by the group of selected surveys. In normalizing the contribution of the Gould Belt, we use results from a recent study that indicates a supernova rate in the Gould Belt of 3 to 5 times that of the local region of the Galactic plane leading to ≈100 neutron stars born in the Gould Belt during the last 5 Myr. Our simulations include the dynamical evolution of the Gould Belt where neutron stars are produced in the plane of the Gould Belt during the past 5 Myr. We discuss the simulated numbers of radio-quiet (those below flux threshold of radio surveys) and radio-loud, [gamma]-ray pulsars from the Galactic disc and the Gould belt observed by [gamma]-ray telescopes EGRET, AGILE and GLAST. They suggest that about 35 of the unidentified EGRET sources could be (mostly radio-loud) [gamma]-ray pulsars with 2/3 of them born in the Galactic disc and 1/3 in the Gould Belt.
Download or read book Cosmic Gamma Ray Sources written by Ka Lok Cheng and published by Springer Science & Business Media. This book was released on 2004-10-25 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma-ray astronomy has undergone an enormous progress in the last 15 years. The success of satellite experiments like NASA's Comp ton Gamma-Ray Observatory and ESA's INTEGRAL mission, as well as of ground-based instruments have open new views into the high-energy Universe. Different classes of cosmic gamma-ray sources have been now detected at different energies, in addition to young radio pulsars and gamma-ray bursts, the classical ones. The new sources include radio quiet pulsars, microquasars, supernova remnants, starburst galaxies, ra dio galaxies, flat-spectrum radio quasars, and BL Lacertae objects. A large number of unidentified sources strongly suggests that this brief enumeration is far from complete. Gamma-ray bursts are now estab lished as extragalactic sources with tremendous energy output. There is accumulating evidence supporting the idea that massive stars and star forming regions can accelerate charged particles up to relativistic ener gies making them gamma-ray sources. Gamma-ray astronomy has also proved to be a powerful tool for cosmology imposing constraints to the background photon fields that can absorb the gamma-ray flux from dis tant sources. All this has profound implications for our current ideas about how particles are accelerated and transported in both the local and distant U niverse. The evolution of our knowledge on the gamma-ray sky has been so fast that is not easy for the non-specialist scientist and the graduate student to be aware of the full potential of this field or to grasp the fundamentals of a given topic in order to attempt some original contribution.
Download or read book Cosmic Mysteries written by Time-Life Books and published by Time Life Education. This book was released on 1990 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides information and explores theories behind such phenomena as eclipses, black holes, gamma ray bursts, star births, and quasars
Download or read book Multiwavelength Approach to Unidentified Gamma Ray Sources written by K.S. Cheng and published by Springer Science & Business Media. This book was released on 2005-05-02 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nearly one half of the point-like gamma-ray sources detected by EGRET instrument of the late Compton satellite are still defeating our attempts at identifying them. To establish the origin and nature of these enigmatic sources has become a major problem of current high-energy astrophysics. The second workshop on Multiwavelength Approach to Unidentified Gamma-ray Sources intends to shed new and fresh light on the problem of the nature of these mysterious sources and the objects behind them. The proceedings contain 46 contributed papers in this subject, which cover theoretical models on gamma-ray sources as well as the best multiwavelength strategies for the identification of the promising candidates. The topics of this conference also include energetic phenomena ocurring both in galactic and extragalactic scenarios, phenomena that might lead to the appearance of what we have called high-energy unidentified sources. The book will be of interest for all active researchers in the high-energy astrophysics and related research areas as well as for scientists and graduate students interested in understanding the recent progress in this field.
Download or read book A Search for Medium Energy Gamma Ray Pulsars written by William Emmett Sweeney and published by . This book was released on 1987 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Very high energy Gamma ray Observations of Pulsar Wind Nebulae and Cataclysmic Variable Stars with MAGIC and Development of Trigger Systems for IACTs written by Rubén López Coto and published by Springer. This book was released on 2016-09-29 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is a comprehensive work that addresses many of the open questions currently being discusssed in the very-high-energy (VHE) gamma-ray community. It presents a detailed description of the MAGIC telescope together with a glimpse of the future Cherenkov Telescope Array (CTA). One section is devoted to the design, development and characterization of trigger systems for current and future imaging atmospheric Cherenkov telescopes. The book also features a state-of-the-art description of pulsar wind nebula (PWN) systems, the study of the multi-TeV spectrum of the Crab nebula, as well as the discovery of VHE gamma rays at the multiwavelength PWN 3C 58, which were sought at these wavelengths for more than twenty years. It also includes the contextualization of this discovery amongst the current population of VHE gamma-ray PWNe. Cataclysmic variable stars represent a new source of gamma ray energies, and are also addressed here. In closing, the thesis reports on the systematic search for VHE gamma-ray emissions of AE Aquarii in a multiwavelength context and the search for VHE gamma-ray variability of novae during outbursts at different wavelengths.
Download or read book Discovery of Pulsations from the Pulsar J0205 6449 in SNR 3C 58 with the Fermi Gamma Ray Space Telescope written by and published by . This book was released on 2011 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the discovery of?-ray pulsations (≥0.1 GeV) from the young radio and X-ray pulsar PSR J0205 + 6449 located in the Galactic supernova remnant 3C 58. Data in the?-ray band were acquired by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope (formerly GLAST), while the radio rotational ephemeris used to fold?-rays was obtained using both the Green Bank Telescope and the Lovell telescope at Jodrell Bank. The light curve consists of two peaks separated by 0.49 ± 0.01 ± 0.01 cycles which are aligned with the X-ray peaks. The first?-ray peak trails the radio pulse by 0.08 ± 0.01 ± 0.01, while its amplitude decreases with increasing energy as for the other?-ray pulsars. Spectral analysis of the pulsed?-ray emission suggests a simple power law of index -2.1 ± 0.1 ± 0.2 with an exponential cutoff at 3.0{sub -0.7}{sup +1.1} ± 0.4 GeV. The first uncertainty is statistical and the second is systematic. The integral?-ray photon flux above 0.1 GeV is (13.7 ± 1.4 ± 3.0) x 10−8 cm−2 s−1, which implies for a distance of 3.2 kpc and assuming a broad fan-like beam a luminosity of 8.3 x 1034 erg s−1 and an efficiency? of 0.3%. Finally, we report a 95% upper limit on the flux of 1.7 x 10−8 cm−2 s−1 for off-pulse emission from the object.
Download or read book High Energy Emission from Pulsars and their Systems written by Nanda Rea and published by Springer Science & Business Media. This book was released on 2011-02-04 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of the inaugural meeting of the Sant Cugat Forum on Astrophysics was to address, in a global context, the current understanding of and challenges in high-energy emissions from isolated and non-isolated neutron stars, and to confront the theoretical picture with observations of both the Fermi satellite and the currently operating ground-based Cherenkov telescopes. Participants have also discussed the prospects for possible observations with planned instruments across the multi-wavelength spectrum (e.g. SKA, LOFAR, E-VLT, IXO, CTA) and how they will impact our theoretical understanding of these systems. In keeping with the goals of the Forum, this book not only represents the proceedings of the meeting, but also a reflection on the state-of-the-art in the topic.
Download or read book GLAST and Suzaku written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Gamma-Ray Large Area Space Telescope (GLAST) is an international and multiagency mission scheduled for launch in the fall 2007. The Large Area Telescope (LAT), the primary instrument of the mission, will survey the high energy sky found to be very dynamic and surprisingly diverse by its predecessor the Energetic Gamma Ray Experiment Telescope (EGRET). GLAST-LAT will have a much improved sensitivity when compared with EGRET and extend the higher energy coverage to (almost equal to) 300 GeV. The instrument is now mounted on the spacecraft and undergoing a suite of pre-flight tests. Data analysis software has been tried out by collaborators in two rounds of 'Data Challenges' using simulated observations including backgrounds. The instrument performance and observational data on selected sources presented here have been obtained through the Data Challenges in the collaborative efforts. There are features in the GLAST-LAT observation possibly unfamiliar to X-ray astronomers: (1) GLAST will operate mostly in the survey mode; (2) the foreground objects (gas, dust, and star-light) become gamma-ray sources; (3) multiple sources will be 'confused' because of the wide point-spread-function. The last two features will pose a challenge for analysis on extended Galactic sources such as supernova remnants and pulsar wind nebulae: multi-wavelength study with X-ray instruments like Suzaku and atmospheric Chrenkov telescopes will become essential to dig out the underlying physics.
